best size of down pipe??

[revs]

im going to install a gt28r but i dont now the down pipe size that i hve to do,whah is the best size tahat i have to do??

 

[350ep70gr]

I use to run gt28rs external wastegated and i had a custom 3 inch down pipe all the way to the side exit. After all 2,5 inch should be enough for almost any gt28 application.

 

[Dane_Bristol]

I don't see why a 2.75-3in downpipe on that sort of turbo is not acceptable.

Different story if you where running a CT9 but that turbo is a large one and i cant see anything wrong with a 2.75-3in downpipe mate to get the best gains without restricting the flow too much.

Me personally i would go for a 2.75in if you can on that sort of turbo setup.

If you are going to be running it at its full potential i would put it at a 3in downpipe.

 

[350ep70gr]

I don't see why a 2.75-3in downpipe on that sort of turbo is not acceptable.

Different story if you where running a CT9 but that turbo is a large one and i cant see anything wrong with a 2.75-3in downpipe mate to get the best gains without restricting the flow too much.

Me personally i would go for a 2.75in if you can on that sort of turbo setup.

If you are going to be running it at its full potential i would put it at a 3in downpipe.

2.75-3in downpipe is also acceptable but not extremely nessecary from my point of view. The theory says that bigger the downpipe -less back pressure is built. Theory also says open flow can cause boost creep. Correct me if i am wrong.

 

[dantheman]

theory also says less back pressure equals less torque/off boost power... theres a compromise with everything, 2.5"-2.75" is recomended overall, unless your running big power/big turbo say 350bhp then a 3" might free up a few extra ponies.

 

[350ep70gr]

theory also says less back pressure equals less torque/off boost power... theres a compromise with everything, 2.5"-2.75" is recomended overall, unless your running big power/big turbo say 350bhp then a 3" might free up a few extra ponies.

x2

 

[Dane_Bristol]

theory also says less back pressure equals less torque/off boost power... theres a compromise with everything, 2.5"-2.75" is recomended overall, unless your running big power/big turbo say 350bhp then a 3" might free up a few extra ponies.

Exactly what i was saying Cheers for the clarification Dan

 

[dantheman]

 

[revs]

ok guys thank you for your help im going to do it @ 2.75